Vacuum ... More or Less?

It would be the same, however the smaller tube would react faster..

Yep - and a larger one woruld provide more of a buffer against system dispurbances.

But realistically, probably doesn't make a great deal of difference.

This is an incompletely formulated dynamic problem.

The engine will draw a deeper vacuum as measured at the downstream end of the tube, but a shallower vacuum if measured at the upstream end.

I'm trying to figure out, if the Engine developes 17"#s @ 1,000 R.P.M. with a 1/4" I.D. tube... If I change it to 1/8" I.D. tube, will I get 18 ~ 20 "#s???

This still does not say where the vacuum is measured. Moreover, the units ("#s) are not correct units.

"#s = inch Hg. Sorry...

No. Pressure is equal on all sides of a vessel. Changing the size, or shape of the tube will not change the strength of the vacuum.

But, advancing the timing would allow more vacuum, if that is an option. Also raising the engine speed should also raise the vacuum. Again, it that is an option. Good luck, what is the project?

Project is: '76 Pinto [2.3 L ~ 2300 c.c. ~ 140 c.i.] with an [ Isky cam: 300 Deg. Dur. & .5" lift.] (2) Weber 2 bbls. each bbl, has a vacuum tube connection ( I made a 4 to 1 manafold ) getting 14 In Hg. @ 1,500 r.p.m. But: I can't get 3rd gear & O.D. on the A4ld Trans. The O.D. is Electric, I don't even know how to connect it.

Is it using DCOE, DGV, etc. (vacuum secondaries)?

The power valve is supposed to help in "low vacuum" situations.

The DGA uses linkage secondaries (more gas into the toilet bowl--worse economy).

All I can tell you it's 2 wires 12v to solenoid which controls downshift....

http://www.therangerstation.com/tech_library/a4ld.html

I have the ATSG Manual... But It don't tell what the wires connect to the Engine/car.

Ranger paper... I got a print - out & put it in my Favorate places, for later refferance.

Thanks for the help.

Diesel vehicles used vacuum for the air cond. controls. To provide vacuum in these cars-trucks they used belt driven vacuum pumps. You could probably rig one of these into your Pinto. Another option would be electric vacuum pumps. A 12 volt air compressor should be able to pull a good bit of vacuum and store and use that.

The electronics of the trans are for another better than I. Good luck.

I have a 12V. Pump... but Trans needs a Variable vacuum. Thanks...